Don't use gas welding rods for tig

I did my due diligence and saw no other posting on this. So here goes.......


I recently ran out of tig rods and have around 10 lbs of gas welding rods. So I had a little project out of steel that needed some filler rod so I did a little test.

Here is what I found. Do not use gas welding rods for tig. You will get porous welds with lots of pits and a very weak weld. I did a little research on this and found that tig rods have higher concentration of silicon and other de-oxidizers that are more suited for tig welding.

I also tried the old standby for gas welding...the coat hanger. I suggest not using coat hangers any more even for gas welding. For tig, coat hangers should never be used as the metal they are made out of are probably your old Toyota with lots of crap in them. I tried one and I was amazed how bad the weld was. Like bird poop blobs everywhere.

I then, just for the fun of it, decided to try mig wire. Specifically ER70S .30 wire. I tried a single strand and found controlling the flimsy wire was tough. So I took the wire, doubled it over and twisted it together with a cordless drill in effect doubling its diameter and making it fairly stiff. That seemed to work. The welding with that was smoother with no porosity at all.

So in a pinch, if you really need to tig weld something say on a Saturday, are out of rods, the LWS is closed and have some mig wire laying around, it may be the answer.

Thats interesting, thanks for the report.
I have hear of using solid MIG wire for TIG before. I seem to recall that those were favorable reports also.
Occasionally I weld some really small pieces, and the er70s2 1/16" rebar that I have is just too large. I've been meaning to try some of the solid MIG wire i have floating around.

Mig wire works fine for Tig. I use it when I need small diameter stainless filler. I have never noticed any difference. The AWS designation on what I have is identical to Tig filler.

What rods do you specifically use for gas welding? In the past, I just used tig rods for gas welding.

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Originally Posted by sportbike

Mig wire works fine for Tig. I use it when I need small diameter stainless filler. I have never noticed any difference. The AWS designation on what I have is identical to Tig filler.

What rods do you specifically use for gas welding? In the past, I just used tig rods for gas welding.

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I use both 1/8 and 1/16 RG45 welding rods for mild steel. I'm using the Cobra 2000 (aka Henrob / Dillon torch). Those RG45 rods sure do not work well when tigging.

I kind of figured out the problem with the welds as I used a rod on a test piece of metal and then an autogenous weld on the same test. The autogenous weld was beautiful but the weld that had RG45 rod added was really cratered and porous.

I am of the opinion that tig welding is a very precise method of welding and that rules need to be followed. I will no longer even try to tig weld using gas rods. I am also of the opinion that gas welding is more forgiving and you can bend the rules and use tig rods.

As well, in a pinch you can also use your aluminum MIG wire with the TIG.

For welding sheet metal or other thin steel solid MIG wire works really well. Like the OP said though it is very hard to control being so thin. The mild steel TIG rods that I have are ER70S2 where as the solid MIG wire I got is ER70S6, I think that designates a higher silicon content, but it does work on thin steel very well if you can hold on to the thin wire. And just like using the ER70S6 MIG wire for thin steel, aluminum MIG wire works great on thin aluminum as well.

For those whom want to use Mig wire maybe a tig pen would help.
https://weldingsupply.securesites.co...UNDEF:X:TP1550
I don't have one but for small filler rod it help.

have fun
Tom

We have a cold wire feeder in the shop at work that is used typical for GTAW machine track welding. We use it for Titanium test welds as well as some other welds. Pretty much required for automated, non autogeneous tig welding.

I have also seen a small handheld end with a variable speed feeder for use when tig welding by hand, using spooled wire.

I have only heard of good reports using MIG wire. Maybe rather than getting thin rods I will have to go get a spool of MIG wire and keep on hand for just this. I should have thought about that when I was tring to get some 309L locally and ended up with something to thick and had a tough time welding with it.

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Originally Posted by everlastsupport

As well, in a pinch you can also use your aluminum MIG wire with the TIG.

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or even better, when welding aluminum if you have any scraps or cutoffs of the actual base metal your welding, that is the best filler. sometimes it can be a pain working the scrap into something you can feed into the puddle, but putting base material back is the best. if you know, u have ran out of rod.

Done that with steel. The same steel, you can not get any better than that. I had a trailer bed (expanded metal) and I use the X piece to finish it off, I was to lazy to walk over and get more filler rod.

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Originally Posted by jerky

or even better, when welding aluminum if you have any scraps or cutoffs of the actual base metal your welding, that is the best filler. sometimes it can be a pain working the scrap into something you can feed into the puddle, but putting base material back is the best. if you know, u have ran out of rod.

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For some alloys (including 6000 series) this is NOT recommend as it can lead to hot crasking issues. Welding of 6061 for example is usually done with 4043 for thinner materials, or 5356 filler for higher strength on thicker sections.

It may not be an issue for decorative items or items where stress is not a concern, however filler metals as recommended by the Aluminum Association or similar should be used for anything that is load bearing.

Also not a good idea for 4130 steel that will not be heat trreated after welding.

I'm gonna go with sportbike on this one. The only time I have ever seen tig rod alloy matching the original base metal is the A356 rod that I paid $33.00/lb for to weld up an aluminum casting. I'm wondering if you could post pictures of your variable speed feeder with the hand-held end. I can see where if I could make something like that up, I'd end up using it more often than not.

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Originally Posted by hooda

I'm gonna go with sportbike on this one. The only time I have ever seen tig rod alloy matching the original base metal is the A356 rod that I paid $33.00/lb for to weld up an aluminum casting. I'm wondering if you could post pictures of your variable speed feeder with the hand-held end. I can see where if I could make something like that up, I'd end up using it more often than not.

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Harbor Freight has a cheap wire feeder that is readily adaptable to Tig. They call it a Mig Welder though ;) .

Thurmond

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Originally Posted by Tritium

Harbor Freight has a cheap wire feeder that is readily adaptable to Tig. They call it a Mig Welder though ;) .

Thurmond

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THAT is truly funny! Funnier yet is that it's true! But seriously a brilliant idea, if it will work with aluminum. I will put the idea high on my "to-do" list after I procure a new TIG welder. (was forced to sell the old linde). Without having to look it up, what's the going rate on HF's cheapest unit?